#include "postgres.h"
#include <strings.h>
#include "fmgr.h"

PG_FUNCTION_INFO_V1(post_crypt);

Datum post_crypt(PG_FUNCTION_ARGS)
{
 char *password, *crypt();
 text *ret;
 long now=time((long *) 0);
 char salt[7];
 strcpy(salt,l64a(now));
 salt[2]='\0'; 
 password = crypt((char *) VARDATA(PG_GETARG_TEXT_P(0)), salt);
 ret= (text *) palloc(strlen(password) + VARHDRSZ);
 VARATT_SIZEP(ret) = strlen(password) + VARHDRSZ;
 memcpy(VARDATA(ret),password,strlen(password));
 PG_RETURN_TEXT_P(ret);
}

PG_FUNCTION_INFO_V1(sql_crypt);

Datum sql_crypt(PG_FUNCTION_ARGS)
{
  char *password, *crypt();
  char s[3], *user;
    /*    *salt=VARDATA(PG_GETARG_TEXT_P(1)), */
  text *ret;

  memcpy(s,VARDATA(PG_GETARG_TEXT_P(1)),2);
  user=palloc(VARATT_SIZEP(PG_GETARG_TEXT_P(0)));
  memcpy(user,VARDATA(PG_GETARG_TEXT_P(0)),VARATT_SIZEP(PG_GETARG_TEXT_P(0)));
  s[2]='\0';
  password = crypt(user,s);
  ret= (text *) palloc(strlen(password) + VARHDRSZ);
  VARATT_SIZEP(ret) = strlen(password) + VARHDRSZ;
  memcpy(VARDATA(ret),password,strlen(password));
  PG_RETURN_TEXT_P(ret);
}


/*
Compile using something like this:

gcc -I/home/postgres/postgresql-6.5.1/src/include -I/home/postgres/postgresql-6.5.1/src/backend -O2 -Wall -Wmissing-prototypes -fpic -I/home/postgres/postgresql-6.5.1/src/include -c -o encrypt.o encrypt.c
gcc -shared -o encrypt.so encrypt.o

And last, you create the trigger in PostgreSQL using this:

create function encrypt(text)
returns text as '/usr/local/pgsql/lib/encrypt.so' language 'c';

If everything is okay, you'll probably have: select encrypt('secret') working
and showing:

encrypt
------------
HPK1Jt2NX21G.
(1 row)
*/